RATIONALE: Drugs used in chemotherapy work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Peripheral stem cell transplant may be able to replace immune cells that were destroyed by the chemotherapy. Monoclonal antibodies, such as rituximab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. It is not yet known if giving more than one drug (combination chemotherapy) plus peripheral stem cell transplant is more effective with or without monoclonal antibody therapy in treating non-Hodgkin's lymphoma.